Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
With moderate winds and 2-4” of new snow forecasted, human triggered wind slabs will be possible on Tuesday. We can expect to see slabs form on northern, easterly and southerly aspects near and above treeline. I expect wind slabs to be on the smaller size; however, some isolated features that collect more snow may hold larger slabs. In addition, surface hoar has been observed near treeline on north facing open slopes. Slabs may run farther and be easier to trigger if the surface hoar gets buried.
Wind slabs tend to form below ridgelines, under cornices and unique features where snow accumulates. Wind slabs can also form where the wind can freely blow snow. Look for clues such as blowing snow, pillow-like features and textured snow surface. A sure sign of slab formation is seeing recent avalanches, cracking and collapsing. Your best bet is to monitor the snow depth by using your ski pole, avalanche probe or just dig down to find the old firm snow surface (melt freeze crust).
I suspect most wind slabs will be on the smaller size, but a small avalanche in steep terrain, above cliffs and near trees can lead to worse outcomes. Use caution in and around terrain traps. If you see these signs of instability, stick to slopes under 30 degrees.